Search Autocomplete

GET /v1/search/suggest:
  query:
    q: "fort"           # prefix
    limit: 10
    locale: "en-US"
  response:
    suggestions:
      - { "text": "fortnite", "score": 98234, "type": "query" }
      - { "text": "fortnite ranked", "score": 45102, "type": "query" }
      - { "text": "fortnite clips", "score": 38901, "type": "query" }

-- Aggregate query log (batch job input)
CREATE TABLE search_query_log (
    query_text   VARCHAR(256) NOT NULL,
    user_id      BIGINT,
    searched_at  TIMESTAMPTZ NOT NULL,
    locale       VARCHAR(8)
);
CREATE INDEX idx_query_log_time ON search_query_log (searched_at DESC);

-- Pre-computed top queries (updated by batch job)
CREATE TABLE trending_queries (
    query_text   VARCHAR(256) PRIMARY KEY,
    frequency    BIGINT NOT NULL,
    locale       VARCHAR(8) NOT NULL,
    updated_at   TIMESTAMPTZ NOT NULL
);

class TrieNode:
    def __init__(self):
        self.children: dict[str, TrieNode] = {}
        self.top_queries: list[tuple[str, int]] = []  # pre-sorted top 10 at this prefix

def suggest(prefix: str, limit: int = 10) -> list[str]:
    node = trie.root
    for char in prefix.lower():
        if char not in node.children:
            return []
        node = node.children[char]
    return [q for q, _ in node.top_queries[:limit]]